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Josh Poimboeuf 900742d89c x86/unwind: Silence warnings for non-current tasks
There are a handful of callers to save_stack_trace_tsk() and
show_stack() which try to unwind the stack of a task other than current.
In such cases, it's remotely possible that the task is running on one
CPU while the unwinder is reading its stack from another CPU, causing
the unwinder to see stack corruption.

These cases seem to be mostly harmless.  The unwinder has checks which
prevent it from following bad pointers beyond the bounds of the stack.
So it's not really a bug as long as the caller understands that
unwinding another task will not always succeed.

Since stack "corruption" on another task's stack isn't necessarily a
bug, silence the warnings when unwinding tasks other than current.

Reported-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/00d8c50eea3446c1524a2a755397a3966629354c.1483978430.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-01-12 09:28:27 +01:00
arch x86/unwind: Silence warnings for non-current tasks 2017-01-12 09:28:27 +01:00
block Merge branch 'for-linus' of git://git.kernel.dk/linux-block 2017-01-04 09:03:37 -08:00
certs
crypto crypto: testmgr - Use heap buffer for acomp test input 2016-12-27 17:32:11 +08:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-01-04 14:14:53 -08:00
drivers Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-01-04 14:14:53 -08:00
firmware
fs Contained in this update: 2017-01-04 18:33:35 -08:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-01-04 14:14:53 -08:00
init mm: add PageWaiters indicating tasks are waiting for a page bit 2016-12-25 11:54:48 -08:00
ipc ipc/sem: avoid idr tree lookup for interrupted semop 2016-12-14 16:04:08 -08:00
kernel smp/hotplug: Undo tglxs brainfart 2016-12-26 17:30:24 -08:00
lib Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-25 14:30:04 -08:00
mm Merge branch 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm 2017-01-01 12:27:05 -08:00
net drop_monitor: consider inserted data in genlmsg_end 2017-01-03 11:09:44 -05:00
samples Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-23 16:49:12 -08:00
scripts gcc-plugins: update gcc-common.h for gcc-7 2017-01-03 12:08:59 -08:00
security Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
sound ktime: Cleanup ktime_set() usage 2016-12-25 17:21:22 +01:00
tools Merge branch 'turbostat' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux 2016-12-25 14:01:28 -08:00
usr
virt Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-25 14:30:04 -08:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS CREDITS: Remove outdated address information 2016-12-21 15:21:29 -08:00
Kbuild
Kconfig
MAINTAINERS Contained in this update: 2017-01-04 18:33:35 -08:00
Makefile Linux 4.10-rc2 2017-01-01 14:31:53 -08:00
README

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.